This invention relates in general to a vacuum cassette to be used in the taking of X-rays where an intensifier screen is employed.
When taking an X-ray, it is known to place the unexposed film next to an intensifier screen so as to increase contrast and thus make possible lower X-ray intensity to minimize patient exposure to X-rays. To obtain effective use of the intensifier, it is important that the unexposed X-ray film be held tightly against the intensifier screen. It is known to achieve this result by placing the film and intensifier screen together in a vinyl envelope, apply a vacuum to the inside of the envelope to collapse the sides of the envelope onto the X-ray film and intensifier screen thereby holding film and screen tightly together. While the vacuum is applied, the open edge of the envelope is heat or pressure sealed and the resulting four-ply sandwich is then ready for use. This loading of the envelope, application of vacuum and sealing must all take place in a darkroom so that the film is not exposed during the process. Special equipment for use in the darkroom is required to effect this known process and the envelope employed can only be used once.
It is a purpose of this invention to provide a simpler, less time consuming and less expensive technique for producing the vacuum cassette.
A further purpose of this invention is to provide a technique which permits reusing the envelope.
Another purpose to this invention is to provide a structure that assures full evacuation across the entire face of the X-ray film and intensifier screen.